金属热处理 ›› 2022, Vol. 47 ›› Issue (12): 162-167.DOI: 10.13251/j.issn.0254-6051.2022.12.028

• 材料研究 • 上一篇    下一篇

稀土元素Ce及热处理对过共析轨钢组织及力学性能的影响

宋冉1, 赵文倩2, 包喜荣1, 陈林1, 王晓东1   

  1. 1.内蒙古科技大学 材料与冶金学院, 内蒙古 包头 014010;
    2.北京北冶功能材料有限公司 材料研究所, 北京 100192
  • 收稿日期:2022-07-30 修回日期:2022-10-20 出版日期:2022-12-25 发布日期:2023-01-05
  • 通讯作者: 王晓东,副教授,博士,E-mail: wxd6595111@126.com
  • 作者简介:宋 冉(1997—),男,硕士研究生,主要研究方向为微合金元素对重载钢轨力学性能及其疲劳性能的影响, E-mail:1456356866@qq.com。
  • 基金资助:
    国家自然科学基金(51461034);内蒙古自治区自然科学基金(2019MS05046,2019LH05013)

Effect of rare earth element Ce and heat treatment on microstructure and mechanical properties of hypereutectoid rail steel

Song Ran1, Zhao Wenqian2, Bao Xirong1, Chen Lin1, Wang Xiaodong1   

  1. 1. School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou Inner Mongolia 014010, China;
    2. Materials Research Institute, Beijing Beiye Functional Materials Company Limited, Beijing 100192, China
  • Received:2022-07-30 Revised:2022-10-20 Online:2022-12-25 Published:2023-01-05

摘要: 研究了稀土元素Ce及热处理对过共析轨钢中夹杂物、微观组织形貌及力学性能的影响规律。结果表明,热处理促进稀土Ce在界面偏聚,充分发挥Ce细化珠光体片间距、净化强化晶界及变质细化脆性夹杂的微合金化作用,并使相变过程充分进行,最终获得均匀连续的精细珠光体片层结构。Ce细化热处理过共析轨钢中珠光体片间距细化至87 nm,细化率高达43.8%,同时细化长条状MnS-MgO夹杂并变为近球状稀土夹杂物,使过共析轨钢获得最佳力学性能,抗拉强度可达1378 MPa,硬度达380 HBW,断面收缩率提高至23.95%,拉伸断口呈现韧性断裂特征。

关键词: 过共析轨钢, 稀土Ce, 热处理, 组织, 力学性能

Abstract: Effect of heat treatment and rare earth element Ce on inclusions, microstructure and mechanical properties of hypereutectoid rail steel was studied. The results show that heat treatment promotes the segregation of rare earth Ce at the interface, giving full play to the microalloying role of Ce in refining pearlite lamellar spacing, purifying and strengthening grain boundaries, modifying and refining brittle inclusions, and making the phase transformation sufficiently completed, so as to finally obtain a uniform and continuous fine pearlite lamellar structure. The Ce refines the pearlite lamellar spacing in the heat treated hypereutectoid rail to 87 nm, with a refining rate of 43.8%. At the same time, it refines the long MnS-MgO inclusions and turns them into near spherical rare earth inclusions, so that the hypereutectoid rail steel can obtain the optimal mechanical properties. The tensile strength reaches 1378 MPa, the hardness reaches 380 HBW, the percentage reduction of area after fracture increases to 23.95%, and the tensile fracture shows the characteristics of ductile fracture.

Key words: hypereutectoid rail steel, rare earthce, heat treatment, microstructure, mechanical properties

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